Insulator



Nov. 27, 1928.

G. I GILCHREST INSULATOR Filed. Oct. 1 8, i919 INVENTOR @eoryf. 63/02/252 IA'IITORNEY Patented Nov. 27, 1928.

I UNITED STATES GEQBGE I. GILCHREST, 0F WILKINSBUBG, PENNSYLVANIA,ASSIGNOR T0 WESTING- 7 HOUSE ELECTRIC 8c MANUFACTURING COMPANY, ACORPORATION OF PENNSYL- VANIA.

msULA'ron.

Application filed October 18, 1919. Serial No. 331,548.

My invention relates to insulators and particularly to insulators of thepillar type.

One object of my invention is to provide a built-up pillar-typeinsulator of ready assembly and of reduced overall length.

Another object of my invention is to provide connecting members fordisposition between the insulating members of a built-up pillar-typeinsulator that shall be symmetrically formed and related to theinsulator and the electrostatic field thereof to ofier a minimum ofdisturbance to said field.

Another object of my invention is to provide connecting means for aninsulator whereby the latter is subjected to compressive stresses only,in response to temperature changes.

Heretofore, it has been usual to construct built-up pillar-type, andother series or endto-end connected, insulators with various forms ofcomplicated connecting devices between the insulatingshells or members.

These have usually employed projecting lugs,

bosses, nuts, bolts and other irregularlyformed portions or members thatdisturbed the electrostatic field of the insulator. Gertain otherinsulators have been so constructed as to subject the insulatingmaterial to expansion stresses of the metal connecting members thereof.

In practising my invention, I provide an insulator, preferably of thepillar type, although certain features thereof may readily be adapted toinsulatorsof other types, that shall be so provided with metal membersdis-' of the insulating members asposed outside to prevent damage to thelatter by expansion of the metal members and that shall be sosymmetrically formed of metal and insulating parts as to improve theelectrostatic field thereof.

I further provide relatively-simple caplike connecting members which,with the insulating members, constitute a series of snugly andsymmetrically fitting units that may be assembled and taken apart withsubstantially the same facility as in certain wellknown plug-and-socketconnectors.

The single figure of the accompanying drawings is a brokenside View,partially in elevation and partially in section, of an in sulatorembodying my invention.

that shall be extremely simple and durable in construction,

In general, my improved insulator embodies a plurality of units 1 eachcomprising an insulating member 2 and end members 3 and 4.

Each insulating member 2, preferably of porcelain, is of'substantiallycup-shape or of tubular form having a transverse wall 5 at one end and apetticoat portion 6 intermediate its ends.

I The end members 3 and 4:, preferably of relatively thin malleableiron, are similar in that they both comprise flanges 7 embracing theends of the member 2. The member 3 is provided with anexteriorly-threaded, outwardly-projecting portion 8 for co-operativeengagement with an interiorly-threaded, inwardly-projecting portion 9 onthe member a, the threads of the members 3 and 4 being preferably formedto facilitate the ready and rapid engagement thereof. It will beunderstood, of course, that the portions 3 and 4, at the extremities ofthe insulator, are adapted for co-operative engagement with conductorand insulator-supporting members (not shown).

The flanges 7 are somewhat larger in interior diameter than the members2 and have serrated 0r roughened inner surface between which and similarsurfaces on the ends of the members 2 bodies of cement are disposed tolloiold the members 3 and 4 securely to the memers 2.

Co-operating raised annular ring portions 10 on the members 3 and 4;serve as seats by which the respective units 1 are held in bindingrelation to each other.

The base member 4 may be provided with angularly displaced perforatelugs or bosses 11 through which screws or bolts (not shown) may beplaced to prevent the insulator from turning about its axis.

The arrangement eliminates cement and metal-from adjacent the insidesurfaces of the porcelain members, thereby preventing fracture of theinsulating material by the expansion of the metal parts undertemperature changes.

In accordance withthe principles set forth in Patent No. 1,129,520,issued Feb. 23, 1915, to K. C. Randall, S. WV. Farnsworth and C. LeG.Fortescue, insulating body for elec-.. tric apparatus, and assigned tothe Westinghouse Electric &.Manufacturing Company, the elimination ofbolts and other projecting bodies, on the exterior surface of theinsulator, and the symmetrical construction and relation of the metaland insulating parts," render the electrostatic field more uniform andreduce the number of positions at which electrostatic stresses mayconcentrate.

lhe electrostatic capacity of the insulator shown is relatively lowbutmay be increased,

as by increasing the area of the metal inside the units, or by varyingthe distance between the members 3 and 4. I

The structure is mechanically very comact, of ready assembly and, byreason of the fact that the metal connecting portions occupy arelatively-small portion-of the axial distance of the insulator, may beof substantially a minimum overall length for a given potential betweenits ends.

While I have shown and described a particular form of my invention,changes may be effected therein, without departing from the spirit andscope thereof, as set forth in the appended claims.

I claim as my invention 1. In an insulator, the combination with a pairof insulating members each having a portion entirely thereacross ofinsulation and embodying a cylindrical portion having a flat transverseend surface disposed in close proximity to the flat-end surface of theother,

of a metal member secured to each of said ends embodying a transversediscoidal portion'in relatively close flat-surface relation to andcontacting with the metal member of the other insulating member, eachmetal member having a uniform relatively smooth outermost perimeter anda central portion for connection to the members having discoidalportions disposed b other, one of said central portions being disposedwithin the plane of the outer surface of its discoidal portion.

2. An insulator comprising two metal in contactingflat-surface-to-surface relation and portions projecting oppositely inthe direction of the longitudinal axis of the insulator, said membersalso having central connecting elements, and insulating members securedto said oppositely-projecting portions and projecting beyond the outerends thereof to provide portions entirely across the insulating membersof insulation, one of said central elements being disposed within theplane of-the outer surface of its discoidal member.

3. A built-up insulating pillar comprising a plurality of insulatingmembers having main body portions of substantially cylindricalflat-endcup-shape, flat discoidal connecting members embodyingrelatively short uniform cylindrical flanges embracing the closed endsof the insulating members and holding portions projecting therefrom, andsimilar connecting members embracing the open ends of said insulatingmembers having holding portions projecting into said insulating membersfor cooperation with said first holding portions, said insulatingmembers having portions entirely thereacross of insulation.

4. A built-up insulator comprising a plurality of hollow insulatingmembers, a relatively-flat transverse connecting member disposed at oneend of each of said insulating members and having a holding portionprojecting outwardly therefrom and a similar connecting member disposedat the other end of each of said insulating members and having a holdingportion projecting into the insulating member and cooperating with theoutwardly projecting holding portion of the next adjacent insulatingmember.

5. A built-up insulating pillar comprising a plurality of substantiallycylindrical insulating members having petticoat portions intermediatethe ends thereof and recesses therein, a metal connecting memberembracing one end of each of said insulating members having anexteriorly-threaded portion projecting therefrom, and a metal connectingmember embracing the other end of each of said insulating members havingan interiorly-threaded portion projecting into one of said recesses forcooperation with the outwardly projecting portion of the next adjacentmember.

6. An insulator comprising an insulating member of substantiallycup-shape, a connecting member of substantially cup-shape embracing theclosed end of the insulating member and having an exteriorly-threadedcentrally-projecting portion and a connecting member of substantiallycup-shape embracing the open end of the insulating member and having aninteriorly-threaded centrally-disposed portion projecting into theinsulating member.

7. An insulator of the pillar type comprising a plurality of superposedinsulating memers having flat cylindrical ends, and relatively fiatsubstantially discoidal metal connecting members therefor disposedtherebetween, said metal members having unobstructed longitudinal outerperimetral holding flanges secured to adjacent longitudinal surfaces ofthe insulating members and integral inner-end portions for connection toeach other in an end recess of one of the hollow insulating members ofeach adjacent pair of insulating members.

8. An insulator comprising an insulating member having cylindrical ends,one of which is recessed, a metal terminal member having a discoidalportion over the recessed end and cylindrical longitudinal flanges, oneof which'embraces and is secured to the re- -cessed end and the other ofwhich, constituting a holding portion, extends into the recess, and asimilar terminal member having a dis coidal portion over the other endof the insulating member and cylindrical longitudinal flanges, one ofwhich embraces and is secured to said other-end of the insulating memvber and the other of which, constituting a holding portion, proj ectsoutwardly from the insulating member.

9. An insulator comprising an insulating member having a recessedcylindrical end and a metal terminal member having a discoidal portiondisposed in flat transverse relation to the longitudinal axis of theinsulator over said end and cylindrical longitudinal flanges, oneofwhich embraces and is secured to said end and the other of which,constituting a holding portion for attaching the'insulator to anexterior member, extends into the recess.

10. An insulator comprising an insulating member having cylindricalends, one of which is recessed, a metal terminal member having adiscoidal portion disposed in flat transverse relation to thelongitudinal axis of the insulator over the recessed end thereof andcylindrical longitudinal flanges, one of which embraces and is securedto the recessed end and the other of which is internally screw threadedand extends into the recess, and a similar terminal member having adiscoidal portion in flat transverse position over the other end of theinsulating member and cylindrical longitudinal flanges, one of whichembraces and is secured to said other end of the insulating member andthe other of which is externally screw threaded and projects out Wardlyfrom the insulating member.

11. An insulator comprising an insulating member having cylindricalends, one of which is recessed, a metal terminal member having adiscoidal portion disposed in flat transverse relation to thelongitudinal axis of the and the other of whichis internally screwthreaded and extends into the recess, and a similar terminal memberhaving a discoidal portion in flat transverse position over the otherend of the insulating member and cylindrical longitudinal flanges, oneof which embraces and is secured to said other end of the insulatingmember and the other of-which is externally screw-threaded and projectsoutwardly from the insulating member, said terminal members each havingan annular raised seat portion on the outer surface thereof intermediatethe said flanges thereon.

12. An in'sulatorcomprising a pair of insulating members having adjacentend portions, a substantially discoidal terminal member secured to oneof said end portions and having a connector portion between the plane ofits outer surface and theinsulating member to which it is secured, and asimilar terminal member secured to the other end portion in relativelyclose substantially parallellane relation to said first-discoidal memberaving an outwardly-extending connector portion for cooperation with saidconnector portion of the first discoidal member.

In testimony whereof, I have hereunto subscribed my name this 8th day ofOct, 1919.

GEORGE I. o LoHREsT.

